There are many applications known in which documents are fed along a paper path and then collated for further processing. Generally, the documents must be properly aligned when the collation is formed before further processing, such as stitching (stapling) or insertion into an envelope, can be performed.
Collating machines accumulate documents, for example, burst or cut sheets from a continuous, perforated web which is fed into the machine and guided towards a path for further processing. In inserter systems, such as the 9 Series.TM. Inserting System sold by Pitney Bowes Inc., collating machines are used in-line with other paper handling equipment as a means of assembling a plurality of sheets of paper into a particular, desired packet prior to further processing, which may include additional collating, stitching, folding and inserting. In a typical paper handling sequence involving an initial output consisting of a plurality of sheets of paper, to be later combined with subsequent output other sheet feeding devices situated downstream, the initial output is fed from a first feeding device, for example, a burster or cutter, seriatim to the collator which collates the output into desired packets. Each packet may then be folded, stitched or subsequently combined with other output from document feeding devices located downstream thereof and ultimately inserted into a mailing envelope. For further background, reference can be made to U.S. Pat. Nos. 3,935,429, 4,547,856 and 4,733,359.
Examples of collating machines used in inserter systems are disclosed in U.S. Pat. Nos. 4,805,841 and 4,640,506 which disclose collators having the capability to collate in standard or reverse order. Collating machines are also disclosed in U.S. Pat. Nos. 4,799,663, 4,925,180 and 4,925,362. The collating machines disclosed in the aforementioned patents use an upper and lower belt and pulley configuration to convey sheets into and collations out of the collating machine. Stop registration wheels are used to stop the forward progress of the sheets being accumulated to form the collation. The stop/registration wheels are wheels which have a section cut out to provide a flat vertical surface which abuts a flat horizontal surface for stopping and aligning the leading edge of the sheets to form a collation.
In U.S. Pat. No. 5,178,379 an improvement to the foregoing collating machine is provided in the form of pivoting stops to register the lead edge of the collation and pinch rollers which apply a normal force to the collation as the belts transport the collation from the collation machine.
While the foregoing collating machines have been found to be suitable for typical collations of less than twenty sheets, such collating machines are not suitable for larger collations of up to fifty sheets.
It is an object of the present invention to provide an improved system and apparatus for accumulating large collations at high speed.
It is another object of the present invention to provide a collating system and apparatus squares the collation as it is accumulated in a stacking area and maintains the squareness of the collation as it is conveyed out of the stacking area.